1. Field of the Invention
A service cable distribution system of the type used for the placement and supply of power cables as well as low tension cables over a predetermined service area wherein the distribution system is of the type embedded and pre-laid into a poured concrete floor in a manner to allow access to specific electrical interconnections between supply channels and distribution channels extending over the service area.
2. Description of the Prior Art
In relatively modern multi floor building construction the use of poured concrete floors having service cable distribution assemblies embedded therein have enjoyed wide popularity. In such distribution assemblies there is normally a central "power closet" or control area serving as a central power distribution or terminal location facility. One or more power cable and low tension cable ducts serving as major supply lines are extended outwardly from this control area in various patterns to supply power and low tension service cables to a predetermined service area. In addition a number of spaced apart distribution lines extend away from, in substantially spaced apart relation from the supply line so as to dispose or arrange for placement of the various service cables to the individual service outlets which supply such power and lower tension services over a given service area. Present day distribution systems normally utilize rather expensive trench header duct which serves as the main supply duct from the control area to the various distribution lines. The expense of such trench header duct is very great due to the fact that a large capacity for interior must be required to carry both the power cable and more bulky and volume consuming low tension cable.
In accordance with UL standards any duct or conduit system housing power cables for the distribution of electrical power must meet certain structural standards such as being made from 14 gage steel, etc. Conventional trench header duct does not separate the power cable duct from the low tension cable duct. Accordingly, the entire structure must be made in accordance with UL standards since in fact high tension or power cable is being maintained therein. To the contrary, low tension duct cable of the type used to supply telephone and intercommunication services throughout a given service area, because of its low tension characteristics does not require the meeting of UL standards. Therefore it is possible for such ducting or conduits to be made and constructed much more cheaply. Further it is normally the practice in positioning or disposing such service cable to cause the physical pulling through of all service cable required from the control area down the trench header duct and completely through the various distribution lines wherein the service cable is pulled through as a single integrally extended line. UL standards again require specific interconnection or splicing between the distribution lines and the supply lines extending from the control area.
The conventional practice of pulling the service cables from the power closet or control area to the distribution ducts via the supply ducts results in a system wherein the circuit breakers for the system are all disposed in the power closet. The inability of the conventional systems to provide means for taking the circuit breakers out of the control area reduces the flexibility of such systems and greatly increases their costs.
The entire system as well as the individual ducting normally required is extremely costly, expensive and often times very inconvenient. Such inconvenience is frequently caused by the disruption of the existing activity being conducted on a given floor and also the temporary destruction and required repair of the existing floor area.
Therefore, a need has been identified in the construction industry for an electrical and service cable distribution system which is capable of low cost installation, adequate access to the service cables and which simplifies the supplying and positioning of service cables from the control area, along the supply route and through the individual distribution lines in an easy manner which will not disrupt the surrounding business activities normally occuring in the serviced area.
The needed system would provide a means for removing the circuit breakers from the control area and provide housing means for said circuit breakers so that they could be disposed at intervals along the supply line. Such housing means should further provide junction box means that would not only house the circuit breakers but would further provide a location for the interconnection of supply and distribution lines. Further, the needed system would provide a layout scheme whereby minimum amounts of space would be filled by the service cable system while simultaneously providing adequate capacity for the bulky low tension cables that form a part of the service system. Accordingly, the new service cable distribution system should provide a novel type of junction box that not only houses circuit breakers, provides an interconnection point for supply and distribution lines, but also is specifically structured and disposed to provide a novel layout scheme that provides adequate accommodation for both high and low tension cables.